1. Field of the Invention
This invention relates to a transcription coactivator in ethylene-responsive transcription factors and further to a method for controlling ethylene-response of plants using the transcription coactivator.
2. Prior Art
Freshness of agricultural products such as crops and flowers is an essential factor to determine their commercial values. On the other hand, ethylene, a plant hormone, controls functions of plant cells during the processes from budding to senescence. Since ethylene, a plant hormone, has a profound effect on freshness, a lot of attention has been paid. The technique to control freshness by controlling ethylene has been a technique dreamed of by producers, distributors and retailers of agricultural products. If it is possible, there is a lot of economical usefulness in preventing overripe fruits and damaged flowers.
For example, a new variety of tomato, FLAVR SAVR®, wherein the expression of polygalacturonase of tomato is suppressed, is well known. Moreover, other trials to prevent overripe of tomato by repressing the expression of the gene of ethylene synthetic enzyme and the production of ethylene have been performed.
Previously, most of the trials in controlling ethylene response were by manipulating genes of transcriptional activation factors, which stimulate promoters of ethylene-responsive genes, or target genes of ethylene. These ethylene-responsive transcription factors (ERFs) have been known as regulatory factors positively controlling the expression of ethylene-responsive genes of plants (Ohme-Takagi, M. and Shinshi, H., (1995) Ethylene-inducible DNA binding proteins that interact with an ethylene-responsive element. Plant Cell 7: 173–182; Suzuki, K., Suzuki, N., Ohme-Takagi, M. and Shinshi, H., (1998) Immediate early induction of mRNAs for ethylene-responsive transcription factors in tobacco leaf strips after cutting. Plant J. 15: 657–665.)
For example, a report of November, 1996, entitled “Development of experimental systems for analysis of the mechanism of biophylaxis and the analysis of biophylaxis” announcing the results of a project on fundamental techniques to develop new experimental system for plants (the second term, 1993–1995), supported by Research and Development Bureau of Science and Technology Agency, tried to elucidate the molecular mechanism of biological control and response of plants by identifying functionally an ethylene-responsive cis-DNA element of biophylaxis gene, which is transcriptionally controlled by ethylene, by testing a reporter gene in transgenic plants and by identifying transcriptional regulatory gene interacting with said element.
Moreover, patent Disclosure 2000-50877 disclosed a method for providing resistance against environmental stresses for such plants as tobacco by introducing transcription factors controlling ethylene-inducible genes.
Still furthermore, U.S. Pat. No. 5,824,868 disclosed a method for lowering ethylene response of plants, wherein a plant is transduced with modified ethylene-responsive DNA, and a method for controlling the expression of said DNA.